JPH0211015Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a sewing machine control device, particularly a single stitch operation control device of a sewing machine.

In recent years, sewing machines that can control speed have been put into practical use. This type of sewing machine is operated by depressing or kicking the foot pedal, and when the pedal is depressed shallowly, the operation is performed at a low speed; when the pedal is depressed deeply, the operation is performed at a high speed. Then, by the turning, the needle raising or the thread trimming operation which is carried out simultaneously with the needle raising is controlled.

During this kind of sewing work, the needle is dropped into the material to be sewn (cloth, etc.) at the start of sewing, and corrections such as overlapping of the cloth are made in this state.In this case, the worker depresses the pedal slightly. The sewing machine is stopped by pressing the pedal in the needle drop state, but since the speed of the sewing machine is fast, it is difficult to adjust the pedal pressure, and if the pedal is pressed for too long, the sewing machine will rotate once. In addition, when sewing securely to the corner of the workpiece or to the end of the workpiece at the end of sewing, the operator should stop the sewing machine slightly before the desired position and press the pedal lightly to prevent stitching from being insufficient or overstitching. The sewing machine is used to add stitches by depressing the pedal, but as in the case above, if the pedal is depressed for too long or the pedal is depressed too much and the speed increases, the sewing machine often rotates one more revolution. It required skill.

As described above, the conventional device had the disadvantage that it was difficult to operate because the speed was controlled only by the pedals as described above.

The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide a sewing machine control device that facilitates single-stitch sewing operations without requiring pedal operations.

In order to achieve the above object, the present invention includes a variable speed motor that drives a sewing machine, a position detector that detects a predetermined position of a sewing machine needle, and a rotational speed of the variable speed motor based on a speed command signal. a control circuit that sets a sewing speed and a predetermined speed lower than the sewing speed and stops the sewing machine needle at a predetermined position based on a position detection signal from the position detector; a one-stitch sewing switch that supplies the control circuit as an external operation signal, and the one-stitch sewing signal controls the sewing machine needle to stop at a predetermined position determined by a position detector at a low speed of one rotation or less. do.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a preferred embodiment of a fixed position stop device for a continuous pattern stitch sewing machine incorporating a sewing machine control device according to the present invention.

In the figure, the sewing machine 10 has one variable speed motor 1.
The conventional device that drives multiple constant speed motors at each predetermined speed has been replaced with one variable speed motor 1.
1, a plurality of operating speeds can be set.

A speed command section 12 is provided to command the operating speed of the variable speed motor 11 described above, and the speed command section 12 is configured as follows. In other words, as shown in FIG.
0, a magnetic sensor section 32 consisting of a Hall element 24 that performs magnetic detection, a magnet 26 that controls the Hall element 24, an amplifier 28 that amplifies the detection signal from the Hall element 24, and a resistor 30; It consists of The speed command section 12 operates an externally provided operating pedal 34 to cause the shielding plate 18 and the magnet 26 to interlock, and in conjunction with this, the optical sensor section 22 outputs a stop preparation speed command signal (hereinafter referred to as "stop"). A sewing speed command signal 204 is outputted from the magnetic sensor section 32, respectively. That is, photointerrupter 1
4 and 16 are shielded by the shielding plate 18, the photointerrupters 14 and 16 output stop speed signals 200 and 202 of "1", respectively, and the magnetic sensor section 32 outputs the Hall element 24 and the magnet. A sewing speed command signal 204 corresponding to the approach distance from the operating pedal 34 is output.
When the distance between the Hall element 24 and the magnet 26 becomes shorter by stepping on the button, the variable speed motor 11
is configured so that the rotation speed is high.

Further, a sewing machine main shaft 36 pivotally supported by the sewing machine 10
is provided with a position detector 40 for detecting the vertical position of the sewing machine needle, and the position detector 40 outputs an upper position detection signal 208 and a lower position detection signal 210, respectively, in response to the rotation of the sewing machine main shaft 36.

Furthermore, a speed detector 41 is provided on the sewing machine main shaft 36 to detect the speed of the variable speed motor 11, and the speed detector 41 outputs a speed detection signal 211 in accordance with the rotation of the sewing machine main shaft 36.

On the other hand, a control circuit 42 is provided on the output side of the speed command unit 12 and the position detector 40 in order to control the speed of the variable speed motor 11, and the control circuit 42 is shown in FIG. It is configured. That is, when stopping the sewing machine needle in order to change the sewing direction during sewing work, the operating pedal 34 is set to neutral and the optical sensor 22 sends "0" to the control circuit 42.
Stop speed signals 200 and 202 are output. In this case, in order to stop the sewing machine needle at a predetermined position, the variable speed motor 11 must continue to be driven at a predetermined preparatory speed, which is slightly lower than the sewing speed, for a predetermined period until the sewing machine needle is ready. A stop speed signal storage circuit (hereinafter referred to as "stop speed FF") is connected to the output end of the Raptor 16 via an OR gate 64.
That's what it means. ) 44 are connected. The stop speed FF 44 continues to output the start signal 212 for a predetermined period even when the stop speed signal 200 of "0" is input from the photointerrupter 16. A start signal 212 output from the stop speed FF 44 is input to a drive circuit 48 (described later) via an OR gate 46, and the start signal 212 is
At the same time as 12, an intermediate speed signal 214 is output directly to the drive circuit 48 as required.

A feature of the present invention is that the sewing machine 10 is provided with an external one-stitch stitch switch 38 that can be manually operated by the operator, and in FIG. It is provided on the arm of the sewing machine 10. Then, the one-stitch stitching switch signal 2 of this one-stitching switch 38
06 is supplied to the control circuit 42 and converted into a differential output signal 207 by the one shot circuit 95.
This differential output signal 207 is supplied to the other input of the OR gate 64.

Therefore, when the one-stitch stitch switch 38 is turned on, a signal having a predetermined pulse width is supplied from the one-shot circuit 95 to the stop speed FF 44 via the OR gate 64, and the variable speed motor 11 is operation can be started at a predetermined low speed, and by the control action described later, the spindle 36 of the sewing machine 10 can be rotated to a predetermined position, and one stitch can be sewn slowly. By turning on the one-stitch stitch switch 38 multiple times, it is possible to repeatedly stop and stop feeding one stitch at a time.

Further, a low speed detection circuit 50 is connected to the output end of the position detector 40.
0 is the lower position detection signal 210 from the position detector 40
This detects that the rotation of the variable speed motor 11 has reached a low speed and outputs a low speed detection signal 216.
FIG. 4 shows a detailed circuit of the low speed detection circuit 50, in which the low speed detection circuit 50 inputs the upper position detection signal 208 from the position detector 40 as a start signal and the lower position detection signal 210 as a reset signal. Input FF52, resistor 54 and capacitor 5
6 and receives the Q output signal 218 of the FF 52; an inverter 60 receives the output signal 220 from the time constant circuit 58;
The Q output signal 218 from the inverter 60 and the output signal 222 of the inverter 60 are input. It consists of a Noah gate 62.

The output terminal of the low speed detection circuit 50 is the stop speed.
It is connected to the reset terminal of FF44, the sewing machine needle is set to the lower position, and the variable speed motor 1
Stop speed only when rotation of 1 reaches low speed
FF44 is reset. As the stop speed FF44 is reset, the drive circuit 48 changes from the stop speed FF44.
At the same time, the start signal 212 of "0" and the intermediate speed signal 214 which had been output as necessary are outputted, and the brake signal 224 of "1" is outputted from the brake one shot circuit 66 provided at the output end of the OR gate 46. The signal is output to the drive circuit 48 and the variable speed motor 11 is stopped.

Furthermore, when stopping the sewing machine needle to trim the thread or raise the needle, the operation pedal 34 is depressed to output a stop speed signal 202 of "1" from the photointerrupter 14 to the control circuit 42. Also, during a predetermined preparation period, the variable speed motor 11 is operated at a predetermined stop preparation speed lower than the sewing speed mentioned above.
must continue to be driven, and for this purpose an FF 68 is connected to the output terminal of the photointerrupter 14. Therefore, based on the stop speed signal 202 of "1" from the photointerrupter 14, the FF 68 outputs a start signal 226 and a low speed signal 228 of "1" for a predetermined period to the drive circuit 48, and also outputs the low speed signal 228 to the sewing machine control circuit 69. A control signal 229 is output. The upper position detection signal 208 from the position detector 40 and the start signal 212 from the stop speed FF44 are passed through the OR gate 70 to the FF68.
The FF68 is reset when the sewing machine needle reaches the upper position, and the FF68 is reset when the sewing machine needle reaches the upper position.
The FF 68 is also reset when the intermediate speed signal 214 is output from the sewing machine control circuit when the sewing machine is pressed down.

Furthermore, the output terminal of the magnetic sensor section 32 and the control circuit 4
2 and the output end of the speed detector 41, a drive circuit 48 is provided to drive the variable speed motor 11 based on the speed command signal from the speed command section 12, and the drive circuit 48 is configured as follows. It is configured as follows.

That is, the magnetic sensor section 32, the control circuit 42
The stopping speed of each output terminal of FF44 and FF68 is V-
It is connected to the speed upper limit comparison circuit 74 and the speed lower limit comparison circuit 76 via the F conversion circuit 72, and the output terminal of the speed detector 41 is connected to the speed upper limit comparison circuit 74 and the speed lower limit comparison circuit 76 via the waveform shaping circuit 78 and the frequency multiplier circuit 80. It is connected to the speed lower limit comparison circuit 76. The speed upper limit comparison circuit 74 is connected to a brake excitation circuit 84 via an OR gate 82, and the speed lower limit comparison circuit 76 is connected to a clutch excitation circuit 88 via an AND gate 86. An abnormality detection circuit 90 is connected to the output terminal of the frequency multiplier circuit 80, and the abnormality detection circuit 90 always outputs a detection signal 230 of "1" to the AND gate 86, thereby detecting a failure of the speed detector 41. In the event of an abnormality such as, a detection signal 230 of "0" is output to the AND gate 86, the excitation action of the clutch excitation circuit 88 is released, and the variable speed motor 11 is stopped.

Speed upper limit comparison circuit 74 and speed lower limit comparison circuit 7
6, based on the start signal 212 from the control circuit 42, the speed detection signal 2 from the speed detector 41 is
11 and each speed signal 204, 2 which becomes a reference speed signal
14 and 228, the rotational speed of the variable speed motor 11 is adjusted. For example, if the speed is lower than the reference speed, the speed lower limit comparison circuit 76 outputs a lower limit signal 232 of "1" to the AND gate 86 to turn on the clutch excitation circuit 88; The upper limit signal 234 of "1" is output to the OR gate 82 to turn on the brake excitation circuit 84, and the variable speed motor 11
to maintain the rotational speed within a certain standard.

The output terminal of the brake one shot circuit 66 of the control circuit 42 is connected to the OR gate 82 of the drive circuit 48.
Brake one shot circuit 6
Based on the brake signal 224 from 6, the excitation action of the brake excitation circuit 84 is performed.

The fixed position stop device in the sewing machine control device according to the present invention has the above configuration, and its operation will be explained below.

To start sewing work, fully depress the operating pedal 34 to move the magnet 26 to the Hall element 24.
from the magnetic sensor section 32 to the drive section 4.
8 and outputs the sewing speed command signal 204 to
Photointerrupter 16 as shown in FIG.
A stop speed signal 20 of “1” is sent from the control circuit 42 to the control circuit 42.
Outputs 0. In conjunction with this, a start signal 212 of "1" is output from the control circuit 42 to the drive circuit 48, and driving of the variable speed motor 11 is started.
Then, the drive section 48 compares the speed detection signal 211 from the speed detector 41 and the sewing speed command signal 204, and if the operating speed exceeds a predetermined upper limit value, the speed upper limit comparison circuit 74 sends "1" to the OR gate 82. ” outputs the upper limit signal 234 to turn on the brake excitation circuit 84, and when the operating speed exceeds a predetermined lower limit value, the speed lower limit comparison circuit 7
Lower limit signal 2 becomes “1” from 6 to AND gate 86
32, the clutch excitation circuit 88 is turned on and the rotational speed of the variable speed motor 11 is held constant.

During such sewing work, if the sewing machine needle is to be stopped with the sewing machine needle stuck in the end of the workpiece, the sewing machine needle must be stopped before the end of the workpiece for the reasons described above. In this case, the operation pedal 34 is neutralized as shown in FIG. 2, and the stop speed signals 200, 202 of "0" are output from the speed command section 12 to the stop speeds FF44 and FF68 of the control circuit 42. Stopping speed FF44
Then, during the period t ₀ until the stop reference is established, the start signal 212 of "1" and the intermediate speed signal 224 as necessary are continued to be output to the drive circuit 48.
The rotation speed of the variable speed motor 11 is set to a predetermined intermediate speed lower than the normal sewing speed, as shown in FIG.
maintained at N ₀ .

During this period of t ₀ , the low speed detection circuit 50 outputs a Q output signal from the FF 52 to the time constant circuit 58 based on the upper position detection signal 208 and lower position detection signal 210 from the position detector 40, as shown in FIG. 218, and along with this, the capacitor 56
Charging is performed only during the period when the Q output signal 218 is output. If the speed of the variable speed motor 11 decreases and the period during which the Q output signal 218 is output becomes longer, the charging capacity of the capacitor 56 will exceed the predetermined value Ec. Therefore, the time constant circuit 58 outputs an output signal 220 that is "1" only during the period when the charging capacity of the capacitor 56 exceeds the predetermined value Ec, so the inverter 60
The output signal 22 from 0 to the NOR gate 62 is "0".
2 is output. Therefore, at the moment the Q output signal 218 from the FF 52 to the NOR gate 62 becomes "0", the low speed detection signal 216 of "1" is output from the NOR gate 62 to the AND gate 64, and the rotation speed of the variable speed motor 11 changes. The conditions are met that a predetermined low speed is reached and the sewing machine needle is in the lower position.

Then, the low speed detection signal 21 is output from the low speed detection circuit 50.
6 is output and a reset input is input to the stop speed FF 44, so a brake signal 224 of "1" is output from the brake one shot circuit 66 to the drive circuit 48, and the variable speed motor 11 is stopped. In this state, when operating the external one-stitch stitch switch 38 to add stitches, the one-stitch stitch switch 38
The needle stitching signal 206 is input to the one-shot circuit 95, and the one-shot circuit 95 outputs a differential output signal 2.
07 and the output signal 2 of the photointerrupter 16
00 and is input to the stop speed FF 44 via the OR circuit 64, and the start signal 212 operates the drive circuit 48 to drive the sewing machine 10. In this case,
Since the pedal 34 is not operated, the sewing speed command signal 204 is not outputted, and the sewing machine is operated at a predetermined speed lower than the normal sewing speed. And again the position detector 4
When the lower position of 0 is detected, the lower position detection signal 210
is output, the stop speed FF 44 is reset by the signal 216 from the low speed detection circuit 50, and the variable speed motor 11 is stopped.

Even when the sewing machine needle is stopped at the upper position, the one shot circuit 95 is activated by the same operation, the stop speed FF 44 is reset, and the variable speed motor 11 is similarly stopped at the lower position of the position detector 40.

In this way, in this embodiment, a pulse is generated at the output end of the external one-stitch stitch switch 38 for a time shorter than the time it takes to rotate the sewing machine from the upper position to the lower position at a predetermined low speed and sufficient to set the stop speed FF44. By providing the one-shot circuit 95, the needle drop at the beginning of sewing and the one-stitch sewing at the end of the object to be sewn can be performed very easily.

When thread trimming or needle raising is to be performed after sewing is completed, the operating pedal 34 is depressed to output a stop speed signal 202 of "1" from the photointerrupter 14 to the FF 68 of the control circuit 42. Along with this
The FF 68 outputs a start signal 226 of "1" and a low speed signal 228 to the drive circuit 48, and also outputs a control signal 229 to the sewing machine control circuit 69. Therefore, in the sewing machine control circuit 69, thread wiping and thread trimming control are performed when the predetermined low speed is reached. And FF68 is "1" from position detector 40
It is reset by the upper position detection signal 208,
The variable speed motor 11 stops when the sewing machine needle reaches a position above the sewing cloth.

As described above, the present invention uses the variable speed motor 11 that drives the sewing machine 10, the position detector 40 that detects a predetermined position of the sewing machine needle, and the variable speed motor 11 based on the speed command signal generated by operating the operating pedal 34. a control circuit 42 that sets the rotation speed of the motor to a normal sewing speed and a predetermined speed lower than the sewing speed and stops the sewing machine needle at a predetermined position based on a position detection signal from the position detector; and the operation pedal 34.
The control circuit 4 is provided separately from the control circuit 4 and is provided so as to be manually operable.
2, and the control circuit 42 controls the one-stitch sewing switch 38 to supply the one-stitch sewing switch 3 to
When a one-stitch sewing signal is received from 8, the rotational speed of the variable speed motor is controlled to a predetermined speed lower than the normal sewing speed, the sewing machine is operated one rotation, and the sewing machine is operated once at a predetermined sewing speed determined by the position detection signal of the position detector 40. Since the sewing machine needle is configured to stop at the specified position, the sewing machine needle can be easily stopped for each stitch of the sewing pattern by operating the single stitch switch without delicately operating the foot-operated operation pedal. Even non-persons can easily sew one stitch, and
The switch for needle stitching is provided separately from the operation pedal and is not used in place of the operation pedal, so if you want to sew one stitch in the middle of sewing, switch the switch each time and press the foot pedal for one stitch. This eliminates the need for the troublesome operation of setting a sewing switch and allows one-stitch sewing to be performed without reducing work efficiency.

[Brief explanation of the drawing]

1 is a schematic configuration diagram showing a preferred embodiment of the fixed position stop device in the sewing machine control device according to the present invention; FIG. 2 is an explanatory diagram showing the detailed configuration of the speed command section shown in FIG. 1; 3 is an explanatory diagram showing the detailed configuration of the control circuit shown in FIG. 1, FIG. 4 is an explanatory diagram showing the detailed configuration of the low speed detection circuit of the fixed position stop device in the sewing machine control device according to the present invention,
FIG. 5 is an explanatory diagram showing the detailed configuration of the drive circuit shown in FIG. 1, and FIG. 6 is an explanatory diagram showing the relationship between waveforms of each part of the fixed position stop device and rotational speed in the sewing machine control device according to the present invention. , FIG. 7 is an explanatory diagram showing waveforms of various parts in the low-speed detection circuit shown in FIG. 4. The same parts in each figure are given the same reference numerals, 10 is the sewing machine, 11 is the variable speed motor, 12 is the speed command unit, 36 is the sewing machine main shaft, 38 is the one-stitch stitch switch, 40 is the position detector, and 41 is the speed detector, 42
1 is a control circuit, 48 is a drive circuit, 50 is a low speed detection circuit, 200 and 202 are stop speed signals, 204 is a sewing speed command signal, 206 is a single stitch sewing signal, 208
is the upper position detection signal, 210 is the lower position detection signal, 2
11 is a speed detection signal, and 216 is a low speed detection signal.

Claims (1)

[Scope of utility model registration request] A variable speed motor 11 that drives the sewing machine 10, a position detector 40 that detects a predetermined position of the sewing machine needle,
The rotational speed of the variable speed motor is set to a normal sewing speed and a predetermined speed lower than the sewing speed based on a speed command signal generated by operating the operation pedal 34, and the sewing machine is started based on a position detection signal from the position detector. Control circuit 42 that stops the needle at a predetermined position
and a one-stitch stitch switch 38, which is provided separately from the operation pedal 34 and is manually operable, and supplies a one-stitch stitch signal to the control circuit 42 when operated. If a one-stitch sewing signal is received from the one-stitch sewing switch 38 without a speed command signal from the operating pedal 34, the rotational speed of the variable speed motor is controlled to a predetermined speed lower than the normal sewing speed to start the sewing machine. A sewing machine control device that operates once and stops at a predetermined position determined by a position detection signal from a position detector 40.